Lung-controlled respiration apparatus



May 31, 1960 H. SCHMITT LUNG-CONTROLLED RESPIRATION APPARATUS Filed June26, 1957 INVENTOR fie/mm S C/111117 2 47217, ATTORN 6 United StatesPatent Ofice 2,938,528 Patented May 31,1960

LUNG-CONTROLLED RESPIRATION APPARATUS Heinrich Schmitt, Lubeck, Germany,assignor to Otto Heinrich Drager, Lubeck, Germany Filed June 26, 1957,Ser. No. 668,193 Claims priority, application Germany June 30, 1956 2Claims. (Cl. 137-64) This invention relates to a lung-controlledrespiration apparatus. In particular, the invention is directed to ahigh-altitude breathing apparatus.

This apparatus is composed of a housing containing an inner chamber andan outer chamber separated by at least one diaphragm forming a partitionwith the lungcontrolled inner chamber communicating with the outerchamber through one or more check valves. Prior to this invention, thecheck valves opened in a direction from the inner chamber toward theouter chamber. During respiration, the apparatus is automaticallyswitched from a vacuum to a pressure operation. Also, the controldiaphragm has its side opposite the respiration inner chamber subject tothe higher pressure. From the diaphragm, this pressure is transferredthrough a crank to a lung-controlled first valve to move it into openposition. Consequently, this first valve, during a breathing intake, isat the higher pressure of the inner chamber, as is usual in the priorart. The respiration air or the oxygen is drawn in under an overpressureand not during a negative pressure.

Several pressure equalization nozzles are used in the apparatus so thatit cannot change automatically from overpressure to negative pressureafter it has been used. A small portion of the metabolic gas underpressure is constantly flowing through these nozzles, which are of sucha small size that the pressure change during an intake breath cannotmaterially decrease.

An overload of the outer chamber or chambers, especially duringirregular breathing, is prevented by fitting overload valves in theouter chamber. Again, the outer chamber is designed and proportioned sothat it can be reached easily so that the opening resistance of theregulating valves can be easily adjusted. The overpressure regulatingvalve can be mounted, for example, in a short tube connecting theapparatus to the face mask, and to serve also as an exhaling exhaustvalve.

The object of this invention is to improve upon the prior art apparatusby adjusting the overpressure and exhaust valve by the movable elementof a spring-loaded aneroid.

The overpressure and exhaust valve is connected to the aneroid so that,when the altitude change occurs at an increasing rate, the closing forceexerted upon the overpressure valve is accordingly increased. Thisproduces the advantage in that, during intake breathing, the desiredoverpressure has been changed in accordance with the pressureexperienced at the particular altitude, and especially increasedpressure changes experienced when the altitude is reduced. Also, as thealtitude is increased,

the overpressure for intake breathing is increased with a certainregularity. In accordance with another feature of the invention, thebarometer aneroid supporting the spring-loaded overpressure and exhaustvalve can be mounted for ready adjustment. This permits the advantage ofbeing able to additionally manually regulate the closing force on thevalve. The aneroid can be axially aligned with a threaded bolt which ismounted on the housing for the apparatus.

The means by which the object of the invention is obtained are describedmore fully with reference to the accompanying drawing, which shows across-sectional view through the apparatus.

As shown in the drawing, the pipe 1 receives the high pressure supply ofmetabolic gas which is then passed into the low pressure housing 2,there being a gas-type connection between pipe 1 and housing 2. The highpressure metabolic gas enters pipe 1 through fitting 3. In pipe 1 ismounted a valve seat 4 upon which rests the head of a spring-loadedvalve 5. Sheet metal plates 6 reinforce a diaphragm 7 mounted in housing2 and constituting a partition dividing the housing into an innerchamber 8 and an outer chamber 9. The diaphragm 7 forming a gas-typeclosure between the two chambers. A crank 10 in inner chamber 8 isconnected between diaphragm 7 and valve stem 11 forming part ofvalve 5.During a period of breathing intake or inhalation, diaphragm 7 moves tothe left and crank 10 lifts stem 11 and unseats valve 5 from seat 4. Themetabolic gas then flows from pipe 1 into inner chamber 8-and throughoutlet tube 12 to the face mask of the user.

When the user exhales, the air passes through check valve 13 and intoline 14 extending from outlet 12 of inner chamber 8 to outer chamber 9.This causes a rise of air pressure in outer chamber 9, the extent of theincrease in pressure being determined by the resistance of exhaust valve21. The next inhaled breath occurs when the previously exhaled air hascaused the increase in pressure on diaphragm 7, as the air in chamber 9cannot escape. The increase in pressure on diaphragm 7 causes crank 10to open valve 4, and this opening occurs before the intake breath canproduce a drop in pressure in inner chamber 8.

Check valve 13 has a small nozzle opening 15 which permits the increasein air pressure in outer chamber 9 to bleed off at the end of therespiration use of the apparatus. This permits the apparatus to returnto its initial operating position.

A housing 20 having opening 20a to the atmosphere is joined to housing 2and communicates with outer chamber 9. Check valve 21, serving as anexhaust valve, is mounted in this housing and is pressed by coil spring22 upon valve seat 23. The opposite end of spring 22 is supported by thebarometer aneroid 24. A bolt 25 is secured by threads 26 to housing 20and adjustably supports aneroid 24. As the altitude is increased,aneroid 24 expands. Accordingly, the opening pressure of valve 21 isincreased, and the pressure of the gas in inner chamber '8 iseffectively raised for the intake breath period.

Manual adjustment of the aneroid 24 in order to change the openingpressure on valve 23 is accomplished by the turning of bolt 25, whichcan be provided with a handle to facilitate turning.

Having now described the means by which the object of the invention isobtained,

' 1. A breathing apparatus for high altitudes comprising a housing, aflexible diaphragm mounted in said housing and forming an inner and anouter chamber in said housing, high pressure gas valve means having aninlet communicating with a source of high pressure gas supply andactuatably connected to said diaphragm and opening into said innerchamber, a gas outlet opening for a face mask in the inner chamberportion of the housing, a

spring-loaded and aneroid controlled overpressure exhaled 10 air exhaustvalve communicating bet ween said outer 2,575,366 Sollman Nov. 20, 1951

